(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 研究了两步热处理对锻造Ti-47Al-2Cr(摩尔分数，%)组织演变和室温拉伸性能的影响。经1290℃，4h→1240℃(FC)，4h，FC+900℃，24h热处理后，锻造TiAl基合金中形成了均匀细小的双态组织，其室温伸长率, 室温抗拉强度和室温屈服强度分别为3.5% , 677MPa和597MPa。在热处理过程中，锻造TiAl基合金发生了复杂的相变，其相变 过程为：变形组织→γf+αf→γf+(αf+γs+αs)→γf+Lf+γs+Ls。当第二步热处理温度偏低时，αs转变为脆性α2相颗粒，降低了合金的室温拉伸性能。
关键字: TiAl基合金；热处理；室温拉伸
TiAl-based alloy made by two-step heat
treatment
（State Key Laboratory for Powder Metallurgy，
Central South University，Changsha 410083，China）
Abstract:The effect of two-step heat treatment on the microstructure evolution and room tensile properties of forged Ti-47Al-2Cr (mole fraction, %) was investigated. After the heat treatment of 1290℃，4h→1240℃(FC)，4h，FC+900℃， 24h，the uniform fine duplex microstructures are formed in forged TiAl-based alloy and its room temperature tensile ductility，tensile strength and yield strength reach 3.5%， 677MPa and 597MPa respectively. The formation of uniform fine duplex microstructures results from the complex phase transformation of forged microstructures→γf+αf→γf+(αf+γs+αs)→γf+Lf+γs+Ls. When the temperature of the second step heat treatment is lower，the transformation of αs into brittle α2 phase particles leads to the decrease of room temperature tensile properties.
Key words: TiAl-based alloy; heat treatment; room temperature tensile
